Oil Getting Into The Intake Manifold?

[Chuck1986]

My friend recently changed the spark plugs on my 2001 Mitsu Eclipse GT for me and he made the remark that there was a disgusting combination of oil and carbon in the intake manifold. I didn't see it myself, so I can only go by what he said.

I'm not too familiar with how blowby works, but does oil get into the intake manifold when blowby occures? Any possible causes for oil getting into the manifold? For what it's worth, the car only has 56,000 miles on it and the PCV valve is as clean as a whistle.

 

[coal68]

Could come from the exhaust gas recicrulation unit, if the car has mods on it (or not, these are popular cars to mod.) and was neglegted the breakdown of the oil will create a sticky substance when it comes back through your intake. This will start to build up and look real nasty. Seafoam or Amsoil are good cleaners to use.

 

[Chuck1986]

quote:

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Originally posted by coal68:
Could come from the exhaust gas recicrulation unit, if the car has mods on it (or not, these are popular cars to mod.) and was neglegted the breakdown of the oil will create a sticky substance when it comes back through your intake. This will start to build up and look real nasty. Seafoam or Amsoil are good cleaners to use.

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Yes, this car is modded!

The EGR valve has been unplugged, since it has aftermarket headers with no place to plug-in the EGR valve. Although wouldn't this actually reduce carbon in the intake manifold, since I do not have that carbon-filled exhaust gas getting re-circulated into the intake manifold?

 

[Leo]

Probably the PCV aswell. Maybe pull it off, give it a clean and then use a catch can.

 

[Gary Allan]

Oil residue is normal in the intake of most engines. It does come from blowby. It's not pretty, but if you're not seeing it exit the fresh air vent and ending up on the upper side of the throttle body, it's being handled by the preferred pathy via the PCV.

As others have said, you can clean it by putting something like Seafoam into the PCV plumbing.